Ubuntu – Ubuntu 18 unity – keyboard (not mouse) freeze, lightdm restart borks system

keyboardlightdmunity

I'm having the following problem within Unity in Ubuntu 18

  • after a while the keyboard becomes non responsive (sometimes, prior to this it behaves like a mouse button is stuck down and mouse movement drags to hightlight text).
  • the mouse moves and the window manager is responsive to it (mouse-hover actions are highlighted)
  • I can CTRL+ALT+F2 to switch to a different user via the usual Ubuntu graphical user login. The keyboard words here to type the user's password, and works within the other user's sesssion
  • if I switch back to the first user, keyboard is broken again.
  • restarting lightdm from the other user breaks the system, and I need to reboot. (I can enter the user's login, something breaks and I'm kicked back to login and need to reboot).

I think we can rule out hardware problems.
Seems like the X-server works OK, since I can switch user.

Ideas on the problem? How to resolve?

Is with Dell XPS 15 9560 laptop.

Best Answer

It turns out that simply tapping touch screen fixes this issue.

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